1. Field of the Invention
The present invention relates, generally, to pumps and, more specifically, to a displacement pump.
2. Description of the Related Art
Conventional displacement pumps known in the art, and in particular hydraulic pumps, typically include a pot-shaped housing, a rotor that is swivel-mounted in the housing and at least one blade that is guided movably inside the rotor. The blade tip is attached at the inner peripheral wall of the housing and divides the internal space into chambers.
In vehicles, the vacuum pumps generate the vacuum in the brake boosters, and usually move permanently along with the vehicle engine. Depending on the speed, this translates into an energy consumption of several hundreds of watts, even though the vacuum required for braking has already been built up.
In DE 2502 184 A1, a refrigerating compressor with blades has been disclosed, in which the blades when they are in a retracted position in the rotor can be locked by notched extensions provided on the blades.
From DE 8517622 U1, a vane pump is known in which a hook space provided between the blades is pressurized for retracting the blades into the rotor.
While displacement pumps known in the related art have generally performed well for their intended purpose, there remains a need in the art for a displacement pump in which the blades can be easily locked in the rotor.